000
FXUS63 KEAX 281746
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1146 AM CST Sat Feb 28 2015
.UPDATE...
Issued at 1144 AM CST SAT FEB 28 2015
Forecast adjustments for our going snow event have been fairly minor
this morning. Models have continued the advertising trend of shifting
the heaviest band of snow a bit farther south with each run, though
with the latest 12Z model runs this southward adjustment is rather
minimal as reality is now catching up to our forecast. Light to
moderate snow has already spread across the Kansas-Missouri border
with snow observations as far east as Sedalia by 11 AM. Have sped up
the spread of the snow across the forecast area based on current
trends, though these adjustments still leave time of arrival for the
snow roughly in the same 6 hour period as previously advertised for
north central to central Missouri. Expectations persist that this
first wave of snow will continue through the day before tapering off
this evening as the first shortwave passes through. We might have
many hours snow free over the late night hours tonight, but also
still think that a secondary band of snow will set up as the surface
high oozes south and frontogenic forcing develops along it leading
edge, though it might be focused just south of our forecast area
tonight.
Further adjustments may be needed this afternoon across areas of east
central Kansas into central Missouri as this area looks like some
banded snow may develop later this afternoon and into the early
evening hours. This should help areas from Butler east northeast through
Clinton, Sedalia and Boonville pick up amounts on the high end of our
forecast today, 4+ inches in central Missouri.
&&
.SHORT TERM...(Today through Monday Afternoon)
Issued at 354 AM CST SAT FEB 28 2015
Our snow maker in the form of an upper level shortwave is evident
moving across western OK/KS early this morning and will continue to
spreading east-northeastward. Expect snow to move into east central
Kansas by about 15Z and quickly spread across the entire CWA this
afternoon. Models have consistently continued to push the initial
main band of snow further south and have trended that way as well.
This would put the main band for today/tonight along the southern
CWA where 2 to 3 inches will be possible using ratios between 10 to
14 to 1. That being said have trimmed back significantly the
northern extent of the snow and have areas along the Missouri/Iowa
border receiving half an inch to 1 inch. Have also lowered
temperatures for today with significant cloud cover and weaker then
advertised WAA. Expect highs mainly in the mid 20s.
Tonight there will be a lull in snowfall as the initial wave pushes
east of the area. However, after midnight/early Sunday morning,
models indicate a frontogenetically forced band of snow will set up
over the area. The NAM continues to be more focus with this band of
snowfall in the vicinity of the I-70 corridor whereas the GFS
continues to depict a broader and more prolonged band of snowfall.
The GFS continues to be the most overdone with this feature then any
of its counterparts so have trend towards the NAM. As such it
appears another half an inch to 2" will be possible with this second
round of snow by Sunday afternoon. All told expect storm total snow
to range from 1 to 2 inches along the Missouri/Iowa border and
mainly 2 to 4 inches further south with a few locations across
central Missouri perhaps approaching 5 inches. Snow should shift
east of the area by late Sunday afternoon as surface high pressure
builds into the area from the northern Plains.
High pressure will shift east of the area on Monday afternoon. This
will cause winds to swing back to the southeast. This will allow
temperatures to warm albeit tempered somewhat by existing snowpack at
that time. Expect highs on Monday to reach into the 30s which is
still some 10-15 degrees below normal for the beginning of March.
.LONG TERM...(Monday Evening through Friday)
Issued at 354 AM CST SAT FEB 28 2015
A highly amplified, positively-tilted upper trough, with the lead
shortwave trough will eject into the Central Plains on Tuesday.
Strong warm air and moisture advection within a broad warm sector is
expected in advance of the upper trough. The initial ascent from the
wave may generate some light precipitation across the area Monday
night. While much of this will fall as a cold rain, the exiting cold
airmass may remain below freezing over the northeast quarter of the
CWA, owing to the possibility of light freezing rain. Impacts should
be minimal, especially with precipitation falling through a +3C to
+6C warm layer above the surface and surface air temperatures in the
lower 30s. Very warm H85 temperatures around +10C will move into the
area by Tuesday morning, temporarily ending any concern of wintry
precipitation. Rain will overspread the entire area on Tuesday as
strong ascent moves over the region. Forecast soundings show a
shallow, skinny CAPE, so with the increasing deep-layer shear and
moisture advection, cannot rule out a few isolated thunderstorms
over the south half of the CWA. Highs on Tuesday will warm into the
middle 40s north to middle 50s south. A cold front will move through
Tuesday afternoon/evening, with some of the lingering precipitation
transitioning to light snow late Tuesday afternoon into Wednesday
morning before the precipitation ends. Confidence is low for any
post-frontal accumulating snowfall. Cold weather with below normal
temperatures and dry weather are expected for Wednesday into
Thursday as surface high pressure builds into the central CONUS and
the upper trough slowly moves eastward, with warming temperatures by
Friday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 525 AM CST SAT FEB 28 2015
VFR conds will cont thru most of the morning hours as a stratus deck
btn 5-7kft across east Kansas will move into the terminals. Further
west across central Kansas lgt snow has begun to fall associated with
a storm system which will cont to progress enewd. Snow is expected to
move into the terminals late this morning btn 16Z-18Z with MVFR cigs
btn 1-2kft and vsbys reduced to 1-3SM. Expect generally light snow to
fall through the afternoon hours before we get a lull in the snow
this evening although MVFR cigs are expected to persist. another
round of snow is then expected to move back into the terminals late
tonight btn 04Z-06Z with vsbys again being reduced to 1-3SM and cigs
dropping into the IFR category. Winds during the TAF period will be
out of the SE veering to the S by the end of the pd btn 5-10kts.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY until 6 PM CST Sunday FOR KSZ025-057-060-
102>105.
MO...WINTER WEATHER ADVISORY until 6 PM CST Sunday FOR MOZ004>008-
012>017-020>025-028>033-037>040-043>046-053-054.
&&
$$
UPDATE...Cutter
SHORT TERM...73
LONG TERM...Blair
AVIATION...73